What is the proper honorific for a transgender person?

Transgender persons have been mentioned a lot in the news recently, particularly with Caitlyn Jenner making the front page of many national magazines and websites. So how should we address transgender and gender-neutral people?

Miss, Mrs, Mr and Ms don’t seem appropriate, so according to this article, the very official Oxford English Dictionary is now considering adding Mx to its next edition as a “stable honorific“. At least in the United Kingdom, government departments, banks, some universities, Royal Mail and driving licences all now accept Mx on their forms, so the OED is following suit.

I’m not quite sure how to pronounce it, or whether it will ever be considered politically correct in the US to address Caitlyn Jenner as Mx Jenner. I would assume she would prefer Ms Jenner though, and Mx sounds to me like a horrific honorific…